1. Technical Field
The present invention relates to optimizing the utility of devices in a wireless communication network and, more particularly, to the determination of precoders that optimize the network utility.
2. Description of the Related Art
The increasing demand for accommodating growing numbers of users within wireless networks has a tendency to limit the signal quality in such networks due to interference generated by serving a large number of users. A useful approach for mitigating the interference in downlink transmissions is to equip the base stations with multiple transmit antennas and employ transmit precoding. Such precoding exploits the spatial dimension to ensure that the signals intended for different users remain easily separable at their designated receivers. To enable precoded transmission, the base stations should acquire the knowledge of channel states or channel state information (CSI).
Many existing works have addressed the beamforming design problem by assuming that each base station communicates with its respective terminals independently. In such a framework, inter-cell interference is simply regarded as additional background noise and the design of the beamforming vectors is performed on a per-cell basis only. Other works assume that both data and channel state information of all users could be shared in real-time, so that all base stations can act as a unique large array with distributed antenna elements. These works employ joint beamforming, scheduling and data encoding to simultaneously serve multiple co-channel users. Moreover existing works also assume that the channel state information is perfectly known to the sources.